Alternative linear structures for classical and quantum systems

The possibility of deforming the (associative or Lie) product to obtain alternative descriptions for a given classical or quantum system has been considered in many papers. Here we discuss the possibility of obtaining some novel alternative descriptions by changing the linear structure instead. In particular we show how it is possible to construct alternative linear structures on the tangent bundle TQ of some classical configuration space Q that can be considered as "adapted" to the given dynamical system. This fact opens the possibility to use the Weyl scheme to quantize the system in different non equivalent ways, "evading", so to speak, the von Neumann uniqueness theorem.Comment: 32 pages, two figures, to be published in IJMP

Appendicitis in a 14-month-old infant with respiratory symptoms

Although appendicitis is the condition that most commonly requires emergent abdominal surgery in the paediatric population, less than 2% of the disease occurs in infants and it is even more uncommon in neonates. In this report, we describe a rare case of a 14-month-old child presenting with abdominal pain first diagnosed with upper respiratory tract infection and then admitted to our Paediatric Surgery Department with a final diagnosis of acute appendicitis. A particular attention has to be kept on children presenting with an upper respiratory tract infection since symptoms can mask abdominal signs. Due to high morbidity and mortality rate related to a delayed diagnosis, appendicitis always has to be considered as a possible diagnosis, in order to ensure a prompt treatment

Response to "Imaging to diagnose acute appendicitis".

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Do we need imaging to diagnose appendicitis in children?

Background: To evaluate the role of clinical assessment with selective use of imaging studies in the management of suspected acute appendicitis in children. Patients and Methods: Medical records of children referred to Emergency Room in 2010 for suspected appendicitis were retrospectively reviewed. Diagnostic investigations divided by age and sex were related to pathological findings. Negative appendectomy and complication rates were calculated. Results: 923 children needed surgical assessment : i0 n 75.7% of them surgical indication was excluded and 24.3% were admitted to surgical ward for observation. Appendectomy was eventually performed in 137 patients (61.9%), 82.4% of them without any preoperative imaging while 17.6% underwent selective studies, mainly abdominal ultrasonography (14.6%). Imaging was requested twice as frequently in not operated admitted children (39.3%) than in the operated ones (17.5%, P < 0.001). Overall complicated appendicitis rate (peritonitis and abscess) resulted 26.4% and negative appendectomy rate 8.8%. Females older than 10 years presented histologically not-confirmed appendicitis in 22.2% of cases, while the younger ones presented more frequently complicated appendicitis (29.3%). Conclusions: Clinical assessment is the key to diagnose appendicitis. Nevertheless, in girls older than 10 years, selected use of imaging should be implemented to avoid unnecessary appendectomies. Imaging of choice in equivocal cases should be ultrasonography

Generalized Reduction Procedure: Symplectic and Poisson Formalism

We present a generalized reduction procedure which encompasses the one based on the momentum map and the projection method. By using the duality between manifolds and ring of functions defined on them, we have cast our procedure in an algebraic context. In this framework we give a simple example of reduction in the non-commutative setting.Comment: 39 pages, Latex file, Vienna ESI 28 (1993

Supra-transumbilical laparotomy (STL) approach for small bowel atresia repair: Our experience and review of the literature

Background : Supra-Transumbilical Laparotomy (STL) has been used in paediatric surgery for a broad spectrum of abdominal procedures. We report our experience with STL approach for small bowel atresia repair in newborns and review previous published series on the topic. Patients and Methods: Fourteen patients with small bowel atresia were treated via STL approach at our Institution over a 5-year period and their charts were retrospectively reviewed. Results: STL procedure was performed at mean age of 3.1 day. No malrotation disorders were detected with pre-operative contrast enema. Eight patients (54.1%) presented jejunal atresia, five (35.7%) ileal atresia, and one (7.1%) multiple ilealand jejunal atresias. Standard repair with primary end-to-back anastomosis was performed in all but one patient. In the newborn with multiple atresia, STL incision was converted in supra-umbilical transverse incision due to diffi culty of exposition. After surgery, one patient developed anastomotic stricture, and another developed occlusion due to adhesions: Both infants required second laparotomy. No infections of the umbilical site were recorded, and cosmetic results were excellent in all patients. Conclusions: Increasing evidence suggests that STL approach for small bowel atresia is feasible, safe and provides adequate exposure for small bowel atresia surgery. When malrotation and colonic/multiple atresia are pre-operatively ruled out, STL procedure can be choosen as first approach. Key words : Jejuno-ileal atresia, mini-invasivesurgery, newborn

Fastening the Initial Access in 5G NR Sidelink for 6G V2X Networks

The ever-increasing demand for intelligent, automated, and connected mobility solutions pushes for the development of an innovative sixth Generation (6G) of cellular networks. A radical transformation on the physical layer of vehicular communications is planned, with a paradigm shift towards beam-based millimeter Waves or sub-Terahertz communications, which require precise beam pointing for guaranteeing the communication link, especially in high mobility. A key design aspect is a fast and proactive Initial Access (IA) algorithm to select the optimal beam to be used. In this work, we investigate alternative IA techniques to fasten the current fifth-generation (5G) standard, targeting an efficient 6G design. First, we discuss cooperative position-based schemes that rely on the position information. Then, motivated by the intuition of a non-uniform distribution of the communication directions due to road topology constraints, we design two Probabilistic Codebook (PCB) techniques of prioritized beams. In the first one, the PCBs are built leveraging past collected traffic information, while in the second one, we use the Hough Transform over the digital map to extract dominant road directions. We also show that the information coming from the angular probability distribution allows designing non-uniform codebook quantization, reducing the degradation of the performances compared to uniform one. Numerical simulation on realistic scenarios shows that PCBs-based beam selection outperforms the 5G standard in terms of the number of IA trials, with a performance comparable to position-based methods, without requiring the signaling of sensitive information

Geomorphology of the northwestern Kurdistan Region of Iraq: landscapes of the Zagros Mountains drained by the Tigris and Great Zab Rivers

We present the geomorphological map of the northwestern part of the Kurdistan Region of Iraq, where the landscape expresses the tectonic activity associated with the Arabia-Eurasia convergence and Neogene climate change. These processes influenced the evolution of landforms and fluvial pathways, where major rivers Tigris, Khabur, and Great Zab incise the landscape of Northeastern Mesopotamia Anticlinal ridges and syncline trough compose the Zagros orogen. The development of water and wind gaps, slope, and karsts processes in the highlands and the tilting of fluvial terraces in the flat areas are the main evidence of the relationship between tectonics, climate variations and geomorphological processes. During the Quaternary, especially after the Last Glacial Maximum, fluctuating arid and wet periods also influenced local landforms and fluvial patterns of the area. Finally, the intensified Holocene human occupation and agricultural activities during the passage to more complex societies over time impacted the evolution of the landscape in this part of Mesopotamia

Benchmarking of graphene-based materials: Real commercial products versus ideal graphene

There are tens of industrial producers claiming to sell graphene and related materials (GRM), mostly as solid powders. Recently the quality of commercial GRM has been questioned, and procedures for GRM quality control were suggested using Raman Spectroscopy or Atomic Force Microscopy. Such techniques require dissolving the sample in solvents, possibly introducing artefacts. A more pragmatic approach is needed, based on fast measurements and not requiring any assumption on GRM solubility. To this aim, we report here an overview of the properties of commercial GRM produced by selected companies in Europe, USA and Asia. We benchmark: (A) size, (B) exfoliation grade and (C) oxidation grade of each GRM versus the ones of \u27ideal\u27 graphene and, most importantly, versus what reported by the producer. In contrast to previous works, we report explicitly the names of the GRM producers and we do not re-dissolve the GRM in solvents, but only use techniques compatible with industrial powder metrology. A general common trend is observed: Products having low defectivity (%sp 2 bonds &gt;95%) feature low surface area (&lt;200 m 2 g -1 ), while highly exfoliated GRM show a lower sp 2 content, demonstrating that it is still challenging to exfoliate GRM at industrial level without adding defects

Benchmarking of graphene-based materials: real commercial products versus ideal graphene

There are tens of industrial producers claiming to sell graphene and related materials (GRM), mostly as solid powders. Recently the quality of commercial GRM has been questioned, and procedures for GRM quality control were suggested using Raman Spectroscopy or Atomic Force Microscopy. Such techniques require dissolving the sample in solvents, possibly introducing artefacts.A more pragmatic approach is needed, based on fast measurements and not requiring any assumption on GRM solubility. To this aim, we report here an overview of the properties of commercial GRM produced by selected companies in Europe, USA and Asia. We benchmark: (A) size, (B) exfoliation grade and (C) oxidation grade of each GRM versus the ones of ‘ideal’ graphene and, most importantly, versus what reported by the producer. In contrast to previous works, we report explicitly the names of the GRM producers and we do not re-dissolve the GRM in solvents, but only use techniques compatible with industrial powder metrology.A general common trend is observed: products having low defectivity (%sp2 bonds >95%) feature low surface area (<200 m2 g−1), while highly exfoliated GRM show a lower sp2 content, demonstrating that it is still challenging to exfoliate GRM at industrial level without adding defects